gnu: libtasn1: Remove obsolete patch.

This is a followup to 6a09628cb1.
(picked from the wrong branch, sorry!)

* gnu/packages/tls.scm (libtasn1)[source]: Remove upstreamed patch.
* gnu/packages/patches/libtasn1-CVE-2017-6891.patch: Delete file.
* gnu/local.mk (dist_patch_DATA): Remove it.

gnu/local.mk

@@ -742,7 +742,6 @@ dist_patch_DATA =						\
   %D%/packages/patches/libsndfile-CVE-2017-8362.patch		\
   %D%/packages/patches/libssh2-fix-build-failure-with-gcrypt.patch	\
   %D%/packages/patches/libtar-CVE-2013-4420.patch 		\
-  %D%/packages/patches/libtasn1-CVE-2017-6891.patch 		\
   %D%/packages/patches/libtheora-config-guess.patch		\
   %D%/packages/patches/libtiff-CVE-2016-10092.patch		\
   %D%/packages/patches/libtiff-CVE-2016-10093.patch		\

gnu/packages/patches/libtasn1-CVE-2017-6891.patch

@@ -1,51 +0,0 @@
-Fix CVE-2017-6891:
-
-https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2017-6891
-
-Patch copied from upstream source repository:
-
-https://git.savannah.gnu.org/cgit/libtasn1.git/commit/?id=5520704d075802df25ce4ffccc010ba1641bd484
-
-From 5520704d075802df25ce4ffccc010ba1641bd484 Mon Sep 17 00:00:00 2001
-From: Nikos Mavrogiannopoulos <nmav@redhat.com>
-Date: Thu, 18 May 2017 18:03:34 +0200
-Subject: [PATCH] asn1_find_node: added safety check on asn1_find_node()
-
-This prevents a stack overflow in asn1_find_node() which
-is triggered by too long variable names in the definitions
-files. That means that applications have to deliberately
-pass a too long 'name' constant to asn1_write_value()
-and friends.  Reported by Jakub Jirasek.
-
-Signed-off-by: Nikos Mavrogiannopoulos <nmav@redhat.com>
----
- lib/parser_aux.c | 6 ++++++
- 1 file changed, 6 insertions(+)
-
-diff --git a/lib/parser_aux.c b/lib/parser_aux.c
-index b4a7370..976ab38 100644
---- a/lib/parser_aux.c
-+++ b/lib/parser_aux.c
-@@ -120,6 +120,9 @@ asn1_find_node (asn1_node pointer, const char *name)
-       if (n_end)
- 	{
- 	  nsize = n_end - n_start;
-+	  if (nsize >= sizeof(n))
-+		return NULL;
-+
- 	  memcpy (n, n_start, nsize);
- 	  n[nsize] = 0;
- 	  n_start = n_end;
-@@ -158,6 +161,9 @@ asn1_find_node (asn1_node pointer, const char *name)
-       if (n_end)
- 	{
- 	  nsize = n_end - n_start;
-+	  if (nsize >= sizeof(n))
-+		return NULL;
-+
- 	  memcpy (n, n_start, nsize);
- 	  n[nsize] = 0;
- 	  n_start = n_end;
--- 
-2.13.0
-

gnu/packages/tls.scm

@@ -58,7 +58,6 @@
       (method url-fetch)
       (uri (string-append "mirror://gnu/libtasn1/libtasn1-"
                           version ".tar.gz"))
-      (patches (search-patches "libtasn1-CVE-2017-6891.patch"))
       (sha256
        (base32
         "0h929bdq6w699y1mdkdajp5a6da8whgg3ba5p4j8x1wy36rlcjll"))))